At approximately 0915
CDT on 10/19/09 a Waterford 3 Moisture Separator Heater shell-slide relief valve (RS-203B) inadvertently opened, causing reactor power to increase from 100% to approximately 100.27% Rated Thermal Power (
RTP). Operations reduced Main Turbine-Generator load by approximately 26 megawatts to restore reactor power to less than 100%
RTP. At approximately 0942
CDT, Operations commenced a rapid plant shutdown because the relief valve would not re-close. At approximately 0944
CDT, Operations manually tripped the reactor due to a low condenser hot well level, just prior to reaching the Condensate Pumps Trip setpoint, to avoid a loss of Main
Feedwater event. The Plant Protection System (
PPS) responded as designed, resulting in an uncomplicated
reactor trip.
Emergency Feedwater Actuation Signal (EFAS) was received on low Steam Generator level as expected from reactor trip at or near full power. Steam Generator levels remained above the EFAS injection level setpoint so that actual injection of Emergency Feedwater did not occur. No other PPS actuation occurred. The plant is currently being maintained in Mode 3.
Waterford 3 plans to commence refueling outage (RF16) at this time, approximately 1 - 2 days earlier than scheduled.
The licensee notified the NRC Resident Inspector.
